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Kim Kardashian had a lot of catching up to do in her first big late-night TV interview since becoming a mom.

On "The Tonight Show With Jay Leno" Wednesday, Kim Kardashian touched on a number of topics--wedding planning, her daughter North West, her engagement to Kanye West and that eye-popping selfie she posted recently in which she flashed major side boob and some serious booty.

Kim, who revealed to Jay that she is "50 pounds down" with the help of exercise and the Atkins diet, explained that all of the criticism directed at her weight while she was pregnant "really did affect" her.

"It really hurt my soul," she said. "It changed how I am in the public a little bit...There were these stories where I was, like, 200 pounds. I was gaining weight because I was pregnant and it was really hard to read all these stories and hear all these nasty things. And I think people sometimes question, they think I'm out 'in hiding' now.

Stars Steppin' Out

"No, I just wanted to kinda adjust my life a little bit because why would I subject myself to so much negativity, especially now that I have a daughter? I just didn't need that energy, I'd rather be in a happy place at home...I've definitely tried to live more of a private life because of that, because they were so nasty. Why even go out as much just to put yourself in that position?"

Talking about how that famous Instagram selfie came to be, she revealed, "I was trying on a bathing suit and I actually just sent that to my boyfriend and I was like, 'Babe, can I post this up? This is like my big middle finger to the world on everyone that called me fat.'"

Well, Kanye was lovin' it, because four days later, they were engaged.

"He did really good...the best ever," Kim said with regard to the 15-carat diamond ring her man picked out for her. "I mean, I know he has good taste, but this is more than I could ever have expected."

Kanye got the stone from jeweler Lorraine Schwartz, "but he's so creative and he's so passionate about everything in life and he wanted to find something--I think he went to four jewelers--to make sure he found the absolute best and had rings designed," Kim gushed about her husband-to-be. "He took so much time and thought put into this and made sure that it was perfect."

As for the next step, the wedding, Kim says that they are "hoping for next summer."

"I don't think we've even had the right time to sit down and talk about it," she said. "I think I'm enjoying just being engaged and I think we're gonna get through his tour and then really talk about when and where and all that."

Kim is thinking destination wedding, "someplace Parisian" perhaps. "Or who knows? I got pregnant when we were in Italy. Maybe Italy? We haven't even talked about it...Maybe I'll pick the place and then he can plan it."

Asked if stepdad Bruce Jenner, who's currently separated from her mom, Kris Jenner, will walk her down the aisle, Kim said "of course."

And she also knows that her name will be a little different after they say their I-dos.

"I'm probably going to have Kardashian as my middle name and then West...My daughter has the last name West and we're a family so I want [my last name] to definitely be West."